Rely on view animations for ResolverActivity

The ResolverActivity (and its subclass ChooserActivity)
already have view animations for animating the share
sheet. Disable the windowEnter/ExitTransition to ensure
that there's just a single animation running.

Test: visual inspection of the transition

BUG: 34234073
Change-Id: I51f6d4d6388e965a4f7efb532f936c207623f938